Marine science

Into the Storm

slide1

Earlier this year I presented some of my findings at the 2016 Australasian Society for the Study of Animal Behaviour Conference in Katoomba. These findinges were based on data collected over the last 2 years during which my field sites have been impacted by 2 cyclones. Below is an adaptation of the talk from the conference.

The Importance of Sociality

slide2There are lots of examples in nature of animals that form social groups. These species gain advantages and incur disadvantages from their social behaviour. For example an advantage might be better predator detection while foraging (known as the “many eyes” hypothesis) while a disadvantage could include higher rates of disease transmission. Studies suggest that the evolution and maintenance of sociality is likely to be influenced by environmental factors. Changes in the environment, like those caused by extreme weather events, are therefore likely to impact upon the social organisation of social species.

For social species, the balance between the advantages and disadvantages of sociality are vitally important in determining reproductive output, competitive ability, foraging success and survival, factors which can ultimately impact on a species’ ability to recover from a major impact.

The Study System

slide3My research focuses on the coral gobies at Lizard Island, Queensland. Coral gobies are small fish, approximately three to four centimeters in length and they spend their entire adult lives within the branches Acroporid corals (corals of the genus Acropora). They suffer high mortality outside of their corals, and as such rarely move between corals once they have established themselves. I have observed up to 16 species of coral goby at Lizard Island which range in social organisation from strictly pair-forming species (which I will refer to as ‘Asocial’ species) to highly social species which can be found in groups of 12 or more (the largest group I’ve found was over 20 individuals).

slide4During my studies, two cyclones have impacted my sites at Lizard Island which has been quite disruptive to my research, but has also presented a rare opportunity to gain an insight into the rarely studied effects of cyclones on social organisation. There is no doubt (unless you’re a cyclone skeptic) that cyclones cause severe damage to the physical structure of the reef. This destruction obviously has impacts on the abundance, diversity and distribution of reef species following the event. For example, obligate reef-dwelling species (species which depend on the structure of coral reefs for protection and food) tend to decrease in abundance while algal grazers tend to increase in abundance. However we know relatively little about how these events affect social structures of reef inhabitants which is a potential driver of the diversity and abundance patterns we observe. As I previously mentioned, social organisation is important in determining factors such as reproduction, foraging success and survival, all of which are critical for a species’ recovery from a major disturbance.

Methods and Results

slide5

We have been surveying sites around Lizard Island since 2014. During these surveys we search each Acroporid coral on our transects for coral gobies. We identify the gobies to species and count the number of individuals living within each coral head (which constitutes a group). We also identify the coral to species and measure it along three axes to estimate an average diameter. I’ve used average diameter in my research so that my findings are directly comparable to previous work which has used this measurement.

The next few slides show some graphs and conceptual diagrams in which I’ve tried to use consistent symbols which I’ll briefly explain. The yellow fish represent ‘asocial’ species (they’re actually pictures of Gobiodon axillaris, a strictly pair-forming species). The green fish represent the social species (these are pictures of G. erythrospilus which is often founds in groups of 3 or 4). I’ve used a little cyclone symbol with an arrow on the graphs to indicate when a cyclone affected the field sites.

slide6We found that social species decreased in group size following each cyclone while asocial species group size remained the same. This indicates that group size decreases observed in social species were unlikely due to direct mortality from the cyclones (otherwise we would have seen a corresponding drop in average group size in the asocial species as well). A year after the first cyclone, the social species had returned to their pre-cyclone group sizes (keep this point in mind as I’ll return to this in a minute). However, a year after the second cyclone the social species had not returned to pre-cyclone group sizes. This may indicate that multiple impacts have longer lasting effects on social organisation.

slide7

Unsurprisingly, we found that coral size had decreased significantly throughout the study. This was the case for for both social and asocial species. The last set of bars on this graph shows the corals that were uninhabited. I’ve included this to illustrate that corals that were uninhabited at the beginning of the study (darkest bar) were of a similar size to the corals that the gobies were inhabiting at the end of the study. This means that at the end of the study, gobies were cramming into small corals that they previously wouldn’t have inhabited.

Let’s return now to that point I made about the social species returning to pre-cyclone group sizes a year after the first cyclone. From the coral size graphs we can see that these larger groups were cramming into smaller corals than before the cyclone.

Why?

I might pause here for a second to explain the underlying mechanism of the hypotheses of social evolution which I have looked at in this study, the ‘ecological constraints’ and ‘benefits of philopatry’ hypotheses. For both of these hypotheses we need to consider the proposition that social groups arise because subordinate individuals make the decision to delay their dispersal (often at a considerable cost to their own reproductive opportunities). The question of why some individuals will delay or forgo their own reproductive opportunities in order to remain within a group is one of the fundamental questions of evolutionary ecology. There are of course other ideas about why social groups arise, but this idea of delayed dispersal is what I will focus on for this study. It is also important to note that these hypotheses are not mutually exclusive and often act together.  So why separate them out? Well, because each hypothesis contains its own set of testable parameters. These parameters can be used to create a statistical model which we test against the real data and we can determine which hypotheses best describe the observed social structure.

Ecological Constraints

slide8This hypothesis looks at ecological factors which might constrain dispersal from a territory such as a lack of available habitat or high predation pressure. In relation to my work, one of the reasons that the social gobies might have re-formed their large social groups in smaller corals could be that they were constrained by a lack of available habitat. i.e. Gobies displaced by the cyclone might have had no choice, but to move into a coral which already had a small group of fish living in it. In this case, we would expect to see that most of the corals would be inhabited because vacant corals would be quickly taken up by gobies dispersing from crowded corals.

Benefits of Philopatry

slide9This hypothesis looks at the idea that animals gain some benefit of remaining on a site that outweighs the benefits of dispersing. For example, the site might be of a high quality which improves the animal’s fitness to survive and reproduce. Dispersing from this site risks, losing this benefit, unless it can find a site which confers the same or better benefits. In my project, it is likely that there was a lot of variation in coral quality following the cyclone. While fish might have quickly moved into whatever shelter they could find, they might have realised later on that their coral was not very good (indicated by the green, algae covered coral in the diagram), and decided that it was more beneficial to vacate their low quality coral and move into a high quality coral (white coral in the diagram) with an existing group of fish. In this scenario, we would expect to find a lower proportion of inhabited corals than we would under the ecological constraints scenario as fish would have vacated low quality corals in favour of high quality corals.

slide10What we found was that after the cyclone, there was indeed a substantial drop in the proportion of inhabited corals. While this doesn’t definitively prove that benefits of philopatry are causing the observed social patterns, it does lend some support to the idea. There was also a drop in the proportion of inhabited corals for the asocial species, but it was not as substantial as that observed for social species. This likely due to a methodological ‘artefact’ which I won’t get into, but suffice to say, for social species, there is some support for benefits of philopatry playing a role in the observed social pattern following the first cyclone. Stay tuned for a more in-depth analysis of this data.

slide11So, in summary, the major findings of this study were that after a cyclone, social species reduced in group size but asocial species did not. A year later social species had returned to their pre-cyclone group sizes, but in smaller corals. There is some evidence that benefits of philopatry are contributing to this pattern. The fact that asocial species did not alter their social organisation could indicate that the asocial strategy is either more robust to such an impact or that it is less flexible. Unfortunately, my surveys were not designed to examine patterns in abundance and I can’t really say whether either strategy is better or worse for recovery following a cyclone. This would be an interesting avenue for further research. Following a second cyclone, social species again decreased in group size, but did not return to pre-cyclone levels another year down the track. This might be because multiple impacts have longer lasting effects on social structure or because corals had reduced to such a small size that they were not capable of supporting larger groups.

Social organisation in social species is influential  in determining survival. The effects of cyclones on social structures has received little attention thus far in the scientific literature. While my research raises many questions, I hope that it can provide a foundation to build upon and move toward  a better understanding of how severe weather events might impact upon social organisation.

I would like to thank my supervisors and field assistants who have contributed to this work. Also a shout out to the Hermon Slade Foundation for funding this research and  the Lizard Island Research Station for accommodating us.

A picture tells a thousand words Jan – Feb Lizard Island trip

I was joined by my sister, Kaz (author of the Madagascan Adventure series) on my latest field trip to Lizard Island. We repeated the surveys that Kylie, Grant and I had conducted last time and ran an experiment to investigate whether a subordinate fish would decide to move out when exposed to an adjacent coral of varying size and with different numbers of fish already residing in it.  I hope you enjoy this visual expose of our time there.

Life at Lizard

The Experiment

For a brief description of the experiment we ran see here.

Day Reef trip

We were honoured to be invited by Anne, Lyle and Alex for a trip out to Day Reef on our day off. It was meant to be a dry day for us, but we were willing to make the sacrifice!

Interesting inkings

downloadBefore we delve into a couple of fascinating media reports which I’d like to share, allow me to apologise for the long interval between posts. There will be a report on my latest round of field work coming shortly. But in the mean time, please enjoy these marine media clippings:

Squid recode their genetic make-up on-the-fly to adjust to their surroundings

Meet Ruby, Australia’s newly discovered seadragon

A small win for the PhD!

I had a small win this afternoon!

I’m back on Lizard Island at the moment and over the last few days I’ve been setting up an experiment.

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This experiment is to try to determine what factors might influence a subordinate individual’s decision to either stay within a group or to move out. I am testing habitat size and habitat saturation. To test these factors I have created groups of three fish (two adults and a subordinate) in medium sized corals. These groups of three are then presented with either a small, medium or large coral containing either 0, 1, 2 or 3 other fish.

Wow! that’s confusing when I write it all out. Here’s a diagram of my experimental design.

Experimental design

Over the last 48 hours Kaz and I have had the first trial running. In trial 1 the group of three fish were presented with an empty coral which was smaller in size. Last night the subordinate actually moved into this smaller coral. I can’t really draw any conclusions from this one trial, but if we keep seeing this happen, it could indicate that the degree of habitat saturation is more critical than the size of the habitat in determining whether a subordinate will stay or leave a group. In terms of group formation, it could indicate that groups are more likely to form when the habitat is highly saturated (i.e. when there are not many vacant corals). That’s exciting for me and my thesis 🙂

More info on my research

My research

Initial project report

Lizard Log series starting here

Lizard pics

Fish tattooing

Fish tattooing

Capturing the fishies

Capturing the fishies

Goby hunting.

Goby hunting.

Kaz shopping for corals

Kaz shopping for corals

Kaz measuring

Kaz measuring

It's not paradise every day...

It’s not paradise every day…

Initial Project Report

Slide1

Last week I presented at the University of Wollongong Post-Graduate Conference. I have adapted my presentation below as it was a good overview of my project to date. By way of some background, each year the biology post-graduate students are set a challenge to incorporate an object or personality into their presentations. This year it was Leonardo Dicaprio, so keep an eye out for some celebrity cameos.

So without further ado, let’s start this talk by having a quick think about why animals form groups. We might imagine that in a perfect world, the ideal way to ensure that you maximise your genetic contribution would be to breed as soon as possible and as many times as possible. This would involve leaving the natal territory as soon as possible to pursue individual breeding opportunities.

Slide2

So why then do we see so many examples in nature of reproductively mature animals which routinely delay or (in extreme cases) completely forgo their own reproductive opportunities in order to join and remain within a group as a subordinate non-breeding member?

The answer is that we don’t really know. We have a few ideas and theories about the costs and benefits of group living, but a general explanation has remained elusive. A major obstacle standing in the way of achieving a general explanation is that there are a lack of studies on marine organisms, which is what my study will focus on.

One of the most promising frameworks with which to study this behaviour is the cooperative breeding framework. This framework contains several hypotheses. I’ll go through just a few which I would like to test and which I will refer to throughout the presentation.

1) Ecological constraints – EC looks at a situation where ecological factors force animals into groups. eg. high predator abundance might cause animals to group in order to obtain a protective benefit through the dilution effect or by making use of discrete habitat patches which provide defence.

2) Life-history – LH hypothesis and EC are closely linked. LH hypothesis looks at inherent life-history traits of animals which might lead to a situation where group formation if more beneficial. For example, animals with long life-spans might cause a breeding habitat to become ‘saturated’. i.e. no vacant breeding ground for new recruits to make use of. In this case it might be more beneficial for the next generation of reproductively mature individuals to join a group and wait for the breeding habitat to become available (avoids conflict).

Most of these studies on birds, insects and mammals to date have either been broad phylogenetic comparisons or fine scale experimental manipulations. Both methods have merit and have in fact been responsible for the huge advances in this field, but there are few studies combining the two approaches. It is important to combine these methods as the broad scale studies can draw correlative conclusions across multiple taxa, but they don’t offer causative explanations. Which is where the experimentation becomes important. However, fine scale experimentation can only focus on a few taxa so the results are often difficult to apply generally across multiple taxa.

So how am I going to approach this question?

I will use a genus of coral reef fishes which show considerable variation in social organisation as a model. Gobiodon species are found in high abundance on tropical reefs. There are over 20 known species.

Slide3

I will start by conducting a broad phylogenetic comparison of the Lizard island population of Gobiodon. This will involve making a genetic phylogeny of the species at Lizard Island (the above picture shows the phylogeny of the Red Sea population). Phylogenies show how closely related species are to each other. Species radiating from a common node are more closely related to each other, than to species originating from other nodes. The nodes represent some common ancestor. Looking at where sociality occurs on this phylogeny is important as we can see whether the behaviour arose at a single evolutionary point or whether it has evolved multiple times. Looking at the tree above, social behaviour does appear to have evolved multiple times.

Using this phylogeny as a base, I can map ecological and life history traits of each species. This will show which traits the social species share and which the asocial species have in common with each other. I will use this information to identify traits to manipulate experimentally to try to induce social behaviour in an asocial species or vice-versa.

I have chosen these fishes because they show great variation in social structure. for example G. histrio is stubbornly pair forming like Romeo and Juliet. While G. rivulatus forms large social groups more akin to the Great Gatsby, although I suspect that there might be some reproductive shares going to subordinate individuals in the Great Gatsby…

Slide4

But back to Gobiodon; they are also highly site attached, which makes observing and cataloguing their social systems, ecological traits and life history traits far simpler and experimenting logistically easier with them. Once they have chosen a coral to settle in, that is where they stay. Even when the water level drops below their corals during extreme low tides, they will hunker down and remain within the coral, exposed to air for a couple of hours. They have a high hypoxia tolerance and air breathing ability which enables them to do this.

Slide5.1

I have chosen Lizard Island in far north queensland as my study site because:

Slide5.2

Click to enlarge

a) it has an exclusive resort where celebs like leo can be found. Unfortunately, they don’t let the researchers stay here. They tuck us around the corner in this photo.

 

 

 

Slide5.3

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b) most of the species of gobiodon are known to occur here (and possibly a new species). It’s also worth noting the size of these fishes in the picture below. The fish in the second and fourth pictures on the top row are actually sitting on my gloved hand.

 

 

Slide5.4

Click to enlarge

c) There is a well established research station here run by the Australian Museum which makes field work and experiments much easier.

 

 

We started this work by finding Gobiodon colonies around lizard island and capturing, counting and identifying the species. To capture the fish we use a mixture of clove oil and ethanol which anesthetises the fish and then we ‘waft’ them out of the coral. Once we capture the fish we hold them in plastic bags until the end of the dive and then take them to a boat to be processed.

Slide7

To build the genetic phylogeny we need to obtain genetic material. I’ve been taking fin clips from the fish for this. We just snip off about 1/8th of the caudal (tail) fin area while the fish are anesthetised. It’s not uncommon to see these fish with much larger chunks taken out of their fins, usually from conspecific disputes. The fins do grow back quickly so we’re not doing any permanent damage to the fish.

While we have the fish on board and anesthetised, we measure their SL and TL and we give them little tattoos. These are a flourescent elastomer tag inserted under the skin so that we can identify the fish again when we come back in order to determine some life-history traits like dominant turn over rates or growth rates or mortality.

To collect the information about the ecological traits to map onto my phylogeny, I have been seeking out Gobiodon colonies and taking Coral measurements.

Slide8

To measure habitat saturation we have been using x-transects centred on a colony of Gobiodon. We move along each axis of the transect and catalogue all of the corals known to be inhabited by Gobiodon species. We record whether they were inhabited or not, what they were inhabited by, how many individuals are in each coral, the size and species of each coral.

This gives us an indication of how many and what types of colonies are surrounding the focal colony and how much available habitat there is in the immediate area.

I need to complete the phylogeny now to map these LH and ecological traits and see if there is any correlation between sociality and these traits.

Slide9.1

The downside to working in beautiful tropical locations is that they are prone to cyclone activity.

Cyclone Ita came right over Lizard Island in April this year. The photos below are taken from the same sites (left to right) before and after the cyclone. In February, my assistants, and I had tagged about 600 individual fish with a plan to come back in 6 months to re-capture and re-measure these individuals and determine growth rates and dominant turn over rates. I returned in August and found 8 of the original 600 tagged fish.

Slide9.2

But moving on, I am still interested in the evolution of social behaviour in these fish, but I will focus more on the evolutionary advantages of sociality or asociality in re-colonising a reef after a disturbance. And I’m hoping that I’ll be able to see that recovery in the data coming out of the x-transects that we’re using to measure habitat saturation.

Anecdotally, there appeared to be more uninhabited corals than there were in February, though I can’t verify this statistically because I used different methods (we were looking at a different question in February). There also appeared to be more juveniles present in August than in February.

Slide10

Moving on to some preliminary results, these tables show the results from a statistical method called a Generalized Linear Model or GLM for short. Don’t worry about that or all of the technical looking numbers, all you need to know is that a significant result is indicated in red or a highly significant result in yellow. For most of the species above, there is a significant result for average diameter of the coral. That just means that there was a strong relationship between the size of the coral (the predictor) and the number of individuals living within the coral (the response). i.e. the size of the coral could be used to predict the number of fish living within it for those species with a significant result.

I’ve found that the group size of some of the social Gobiodon species is related to the coral size, but not to the size of the largest individual (alpha), which is interesting as Marian Wong and Pete Buston (who presented at UoW a couple of weeks ago) had found that there was a relationship between both coral size and the size of the alpha with the group size in the anemone fish Amphiprion percula. G. oculolineatus does appear to follow this pattern. What I can take away from this is that the determinant of group size is probably species specific and will therefore be more difficult for me to make general conclusions about.

Looking at some of the before-after cyclone data that was comparable, the corals that did survive the cyclone showed positive growth. However when we looked at the site as a whole, the average size of the corals had decreased. This was to be expected since, as you can imagine, a major disturbance like a cyclone would smash up the larger corals into smaller corals. The smaller corals also have less surface area so are more likely to survive a cyclone.

Slide11

I’ve also found that, as you would expect there was a decline in the coral goby abundance. However, the second graph is more interesting. Some species, like G. erythrospilus, G. rivulatus and G. unicolor appear to be occurring in larger groups post-cyclone. This is possibly an indication that they are in a phase of recruitment.

Slide12

This will require further exploration so I have another trip planned for January. During this trip I will be re-conducting the x-transects in order to examine this trend across multiple sites. What I will be looking for is whether there is a detectable shift in the goby community. There might be a higher proportion of social species present which could indicate that social species have some kind of advantage in recolonising a reef after a disturbance (or vice-versa).

Slide13

I will now need to finish the genetic phylogeny and map on the ecological traits that I have collected so far. I have another round of field work booked in for January. I will be conducting more of the cross transects to see if there has been a detectable community shift since my last visit. I also want to set up a pilot experiment looking at the effects of habitat quality and habitat saturation on a subordinate individual’s decision to move or not.

I would also like to set up and run the life history traits work again. i.e. the capturing and tagging component, as this is a really important part of the cooperative breeding framework which I’d like to explore.

To finish up I’d like to say a final thank you to my assistants for their help in the field. It really is a big commitment for them to come and help me out for weeks at a time. Thank you very much! My work could not happen without your help.

Slide14

If anyone has any questions about my project, please leave a comment below. Thank you!

GobyPro issue 2

Welcome to the second edition of Gobypro!

It’s been quite a while since the previous post of GobyPro and we’ve been out in the field collecting more photos.

As promised in the last issue of GobyPro, Oranges are up first. We called these guys ‘Oranges’ because their species name is citrinus, which kind of sounds like citrus. G. citrinus is found mostly in big bunches of staghorn corals like A. intermedia. We usually saw them in large groups with two dominant breeders. These are the giants of the Gobiodon world, reaching sizes of up to 6.5 cm! Despite their massive size they were extremely difficult to capture as they would retreat right down into the coral. I really want to capture a few groups of these ones to see if they have a distinct size based hierarchy, but no luck so far. While I was diving in Indonesia recently, we found a group of G. citrinus which were black in colour.

G. citrinus

G. citrinus

G. citrinus black variant

G. citrinus black variant

Next we have the lemons, G. okinawae. These gobies are a very distinct bright yellow – hence the nickname “lemons”. We also called them lemons because we often found them living with a G. citrinus colony, forming a pretty little underwater orchid. Unlike most other species of Gobiodon, the lemons are the only species in this genus which like to hang out at the branch tips of the corals and often hover above and even move between corals. We found individuals ranging from 1.0 cm to 3.5 cm.

G. okinawae

G. okinawae

Goby Trivia

Some species have a high hypoxia tolerance and air breathing ability, meaning that they can stay in their corals even if the coral becomes exposed at extreme low tides.

Nilsson et al. 2004. Coward or braveheart: extreme habitat fidelity through hypoxia tolerance in a coral-dwelling goby

We saw this incredible ability on the last field trip during a king tide.

A G. erythrospilus, high and dry

A G. erythrospilus, high and dry

In the next issue of GobyPro:

An unidentified species of goby that we found on our last field trip.

Contact Form

 

 

Lizard Log 26/8/14 – 30/8/14

Day 25 26/8/2014

The wind had dropped slightly this morning so we braved the lagoon again. We went to a site on the edge of the Palfrey reef system which I hadn’t been to before. The coral there looked to be in quite good condition. It would be worth doing some more transects along there. It was a bit surgy underwater, but the reef gets a bit of protection from the Bird Island reef. As we were swimming back to the boat, after completing our transects, we found a huge plate coral with a big school of sweet lip under it. They were pretty curious and came right up to Kylie for a photo.

Sweet lip hanging out under a plate coral.

Sweet lip hanging out under a plate coral.

We did our second dive on another section of the same reef. We decided to try this section because we were on a falling tide and the reef edge was deeper than the first site. Unfortunately the reef edge had none of the corals we needed, so we went up onto the reef flat. It was nice and protected in behind the big Porites bommies which made up the reef edge. We found a few G. brochus colonies up there which was good as I haven’t been able to do too many transects on them yet. It just takes me forever to find the little buggers as they bury themselves deep in A. loripes heads, which are really dense.

As we were heading back to the boat, we found several artificial reefs out on the sand. One of them had a plastic cage over it. It looked like an abandoned caging experiment. We took a couple of photos and then headed to the boat. We told the director about them and found out that it was a really old experiment, long since finished. They will be removed soon. It’s a bit of a shame as they now have quite a bit of growth on them. But it is a good reminder that we need to remove all of our equipment from the field when we’ve finished. Especially when working in a World Heritage area.

Old experiment left in the field.

Old experiment left in the field.

This afternoon we said farewell to the two Australian Museum researchers who had been our lab buddies for the last five days. They were good fun to share a lab with.

Day 26 27/8/14

Today we went back to the same reef system we’d visited yesterday. The wind had picked up again, but it was still quite manageable underwater. We got some great data over our two dives. The only downside was that the battery on the GoPro ran out so we couldn’t take photos of the corals on our second dive. It’s not essential, but it helps with coral identification and I’m planning on revisiting all the photos to make a visual complexity estimate of the corals.

We found a couple of beautiful big Nembrotha nudibranchs (I think) on our first dive.

Nudibranchs

Nudibranchs

Day 27 28/8/14

Kylie and I headed out to Palfrey again today. One of the Bshari lab group students came out with us today. She was documenting wrasse interactions with cleaners. She snorkelled around the boat, following fish, while Kylie and I went about our business. Luckily, she is Swiss, so she didn’t get cold on the surface while Kylie and I froze on our two 90 minute dives. Acclimatisation is a …. not very nice thing….

Kylie spotted an octopus watching us from a hole in a coral head on our second dive. After we’d completed the transect near our friendly cephalopod, we swam off to find a new transect site. When we found a good spot, Kylie swam back to collect the transect and bring it to our new site. She swam past the octopus’ hidey hole, but it wasn’t there anymore. When she got to the transect, the octopus was there checking it all out, running its tentacles over the PVC tubing and tape measures. When it saw Kylie it ducked into a hole, but kept one tentacle on the transect. They’re such inquisitive animals!

Curious cephalopod

Curious cephalopod

Kylie and I were both feeling quite tired in the evening so we decided to have an early dinner and get an early night. I love socialising here with the housemates, but it was so nice to lay down and turn my brain off early.

Day 28 29/8/14

Kylie and I had a bit of a later start today because our resident baker, had made bacon and cheese rolls for breakfast. Delicious! I’ve said it before and I’ll say it again; Awesome housemate!

The wind was blowing hard today. We had a pretty rough boat ride out to our site today. Kylie and I were both feeling pretty knackered today so we decided to just do a single dive at Trawler Beach. Under the water, the conditions were quite manageable and we got four transects completed.

Kylie being useful

Kylie being useful

Bumpy boat ride

Bumpy boat ride

This afternoon I got stuck into organising my data. It’s a big job so it’s good to get a head start on it before I get back from the field. I also took the opportunity to catch up on the emails that have been building up and filling in some of the collection forms for the various permits and databases I’m a party to.

Day 29 30/8/14

Kylie and I got back out to Trawler today for our dives. The wind was still blowing hard on the surface, but underwater was fine. It felt cold though! I’m going to have to resort to zipping up my wetsuit I think.

We decided to pick our way through the patch reefs and head to Trawler Beach for our surface interval. We took shelter at the eastern end of the beach, near the mangroves. The water was beautiful and still there and it was reasonably out of the wind. It was still a bit cold though as it was a pretty overcast day. I know we’re supposedly in the tropics, but it is cold in a wet wetsuit with a 30 kt wind.

Trawler Beach

Trawler Beach

As I was donning my dive gear in the water for the second dive, a big green turtle came up from the reef to see what was happening. It circled me and then casually swam off when Kylie turned up with a camera. It had two great big remoras accompanying it. One of the remoras was bigger than the poor turtle’s shell!

It was BBQ night again tonight. The decision was made to hold the BBQ in the beach house because of the wind. Although the wind had dropped by the time we went down to the beach for sunset drinks and it was actually quite pleasant. It’s more intimate in the beach house though and you can talk to more people so it was fine.

Sunset

Sunset

Lizard Log 22/8/14 – 25/8/14

Day 22 23/8/14

We got moving early today to take advantage of the high tide. The wind was really strong today. We did a dive at horseshoe but got knocked around a lot there. We were copping swell from 2 different angles. Our transect setup kept falling apart. It took us 45 minutes to run 1 transect. Previously, we managed to get three transects in about an hour at this site.

Our second dive was much nicer. We dived the reef between Bird Island and South Island. It was still blowing a gale on the surface, but underwater was fine. We managed a few more transects and then called it a day.

It was BBQ night tonight. We met a few more of the tradies working on the resort and had a good catch up with some of the other researchers here.

Day 23 24/8/14

Did a couple of good dives today. The wind was stronger again than yesterday so we tried to target a slightly deeper reef in order to avoid the surface swell. By deeper, I mean 4 m. We did our first dive on a bommie between Bird and South Island. There wasn’t a lot of acroporid coral there, but we got enough for a couple of transects. The dive itself was quite nice. I saw the biggest sweet lip I’ve ever seen! The photo doesn’t really do it justice.

Big sweet lip

Big sweet lip

We did our second dive on the reef adjacent to the bommie. There was more acroporid growth, but the site had been hit pretty hard by the cyclone. My partner, Kylie, found a couple of beautiful little pipefish.

pipehorses

pipehorses

In the afternoon, we took a couple of the guys working with the Australian Museum up to Mermaid Cove.  The ride up was a bit bumpy but the cove itself was nice and protected. The two guys went off to collect gastropods while Kylie and I went for a snorkel. There was a lot of damage from the cyclone there. Some stretches of reef were just bare rubble with the odd clam poking through. We did find a big Porites bommie which was packed with tropical rock lobsters and there is still plenty of fish life around. Just not many gobies 😦

Rubble

Rubble

Tropical rock lobster

Tropical rock lobster

Looking for gastropods

Looking for gastropods

Day 24 25/8/14

The wind was crazy this morning! We actually decided to head back to the Clam Gardens for our dives today because the conditions in the lagoon were atrocious. As we rounded Osprey Islet, the wind, which funnels through the little valley where the airstrip is located, hit us hard. There was so much spray that I had to stop the boat to get a sense of where I was headed and put my mask on for the rest of the trip.

At the Clam Gardens, the wind was still blowing hard, but it is so close to shore that the wind doesn’t have enough distance (fetch) to stir up much of a swell. We did our two dives there, but were stretched pretty hard to find enough Acroporid corals. At least we weren’t getting pummelled underwater, but the trip back kind of made up for it! The boat was almost airborne a couple of times. I was on and off the throttle most of the way back. I’d go as far as saying that it was probably the worst conditions I’ve seen at Lizard. I’m sure it gets worse, but I’m yet to experience that joy.

In the afternoon, I took the two Australian Museum guys up to Watson’s to look for more gastropods. One of the station volunteers also decided to join us. She’d heard that there were octopus in Watson’s Bay and really wanted to see one.  The wind had thankfully died down a bit by the time we departed so we had a bumpy, but not uncomfortable ride up there. I decided to stay dry (although I got soaked on the drive up there!) and go for a walk. I decided to have a look along the Pandanus Track so I strapped on the hiking boots and set off. The track runs behind the dunes to a little paperbark swamp. It wasn’t a massive walk, but it nice to be out of the wind for a little bit.

The trusty old hiking boots

The trusty old hiking boots

Unfortunately, no one else had much success this afternoon, but everyone was happy. The boys only found a handful of gastropods, most of which they’d already collected and there were no octopus sightings. So we headed back for a warm shower. But then there was no hot water because it’s a solar system and it’s been overcast all day. The first world problems just keep on coming!

Lizard Log 18/8/14 – 21/8/14

Day 17 18/8/14

Grant and I went out to Lizard head again today. I have decided not to focus on re-capturing the fish from this site because, even if I get most of the fish from here, it would only be a tiny fraction of all the fish we collected last year so I’m not going to have the numbers to run any reliable analyses. But I wanted to get some more habitat saturation data from there while the conditions allowed us to dive there. We got six transects done in the morning before the wind picked up too much so that was excellent!

By the end of our dive the wind was getting quite strong so we dashed over to Ghost Beach again to take shelter and eat some lunch. We had the rest of our crumbed fish in wraps with some lettuce and chilli mayonnaise. Almost as good as last night’s dinner!

For our second dive we headed over to Big Vickey’s reef. It was quite uncomfortable on the surface because the swell wraps around Palfrey Island there and the wind had us anchored side on to the swell. So we geared up quickly and jumped in. This was the deepest dive we’d done on the trip so far at a whopping 8m! It was much better down there out of the swell. We ran a few more transects then headed back to the boat. On the way back we saw two huge stingrays buried in the sand. One of them had a remora sheltering under its tail.

Stingray lifting off

Stingray lifting off

Remora sheltering under a stingrays tail

Remora sheltering under a stingrays tail

Back at the station, I had a cooking lesson with one of our housemates, who bakes just about every day for us! Such an awesome housemate to have 🙂 I had heaps of bananas which were getting a bit old so we whipped up a big batch of banana bread only to realise that we don’t actually have a bread tin here. We ended up making the mixture into muffins which worked a treat!

Day 18 19/8/14

It was Grant’s last wet day today. Great news for him as he’s headed home to his family on Thursday. It’s melancholy news for me because he’s been a fantastic help over the last few weeks and I’ll miss his company, but with his departure comes the arrival of my partner which I’m really looking forward to.

There was a conversation at sunset drinks last night about fieldwork volunteers. One of the researchers wasn’t too impressed with their assistant. This particular assistant was a lovely person, but apparently wasn’t very helpful in the field. I must say that I’ve been really impressed with all of the people who’ve helped me out with my research, past and present. But the conversation was a good reminder that good research assistants are worth their weight in gold! I’d like to just take a moment here to say a great big thank you to all research assistants, especially mine, who have been awesome! Without you guys these projects couldn’t happen. You really are the unsung heroes of the research world!

But back to our day. We smashed out six more transects at Lizard Head this morning and then another four at the reef off Trawler Beach. The tides were really low again so they weren’t really dives. My tank was out of the water most of the time. Again. But we got a heap of really good data so it’ll be worth the crummy diving conditions.

Searching for gobies at Lizard Head

Searching for gobies at Lizard Head

We had the Bashari lab group over for dinner tonight. There was an amazing spread and it was all delicious!

Day 19 20/8/14

It’s Grant’s dry day today before he flies out tomorrow. He’s headed out fishing with Bruce and Cassie for a couple of hours. This morning I went over to Picnic Beach with one of our housemates. She needed to gather some water samples over there and I wanted to see if any of the G. ceramensis  had survived. There was quite a bit of S. hystrix that survived the cyclone, but many of them were uninhabited. There were a few G. ceramensis so I’d like to head back there with my partner, Kylie, when she arrives and do some transects.

Kylie will be leaving this afternoon to join me here tomorrow morning. I’m very excited to see her!

I’ve been doing some data analysis this afternoon, looking at whether habitat saturation differs between social and asocial species. The initial verdict is no. Which is a little disappointing, but hey, results are results. I haven’t finished gathering the data yet and there is quite a bit of variance, so more data could reduce that, but there really doesn’t seem to be any pattern there. This basically means that I should start thinking about another variable which might influence the social behaviour of a species.

Initial analysis looking at the difference between social (S) and asocial (AS) species in the proportion of inhabited corals per habitat. No significant difference here.

Initial analysis looking at the difference between social (S) and asocial (AS) species in the proportion of inhabited corals per habitat. No significant difference here.

I asked one of the researchers here for some advice on the statistics this afternoon and she told me the one thing that all scientists dread – that I have a fundamental error in my data collection. These kinds of errors can’t be fixed and will be present in any kind of analysis and of course in the eventual interpretation of results. The issue is one of non-independence with placing my transects. I think the data will still be useful for species associations, but I probably can’t use it for habitat saturation. So now I’ll just need to draw the link between species associations and social behaviour.

Day 20 21/8/14

Kylie arrived just before 8am this morning! It was fantastic to see her! After a bit of breakfast we got through the diving and boating inductions and set about preparing to head out for the afternoon. No rest for the wicked! 🙂

The tide was so low that we had to walk the boat over to Loomis before we could put the engine in the water. On the way over we saw a group coming back in from collecting some pH probes. They were doing it on snorkel and weren’t able to free the marker buoy so they asked if we’d be able to collect it for them.

We jumped in at Picnic beach for our first dive and ran a few transects. Sadly most of the corals we found there were vacant. We did find a couple of G. ceramensis and we also found a big coral colony which had four different goby species co-inhabiting it. After wards we went around the corner and jumped back in for a quick dive to retrieve Gabby’s marker buoy.

For our second dive, we went over to Lizard head again and ran some more transects there. The wind wasn’t very strong today so diving in the shallows there was quite fine.

Lizard Log 14/8/14 – 17/8/14

Day 13 14/8/14

The conditions today didn’t look too bad when we were loading the boat. We headed back to the patch reefs around Palfrey for our surveys. The wind was still blowing quite strong, but there wasn’t a great deal of swell so we geared up and got in the water. We conducted our transects and got some more great data. By the end of our fourth transect, we’d been in the water for over 90 minutes so we called it quits. It felt like we were getting thrown around a bit more by the end of the dive, but I put it down to the falling tide. When we got back to the surface though, the wind had really picked up and the boat was pitching heavily and swinging on the anchor. These are only little 5m tinnies so it doesn’t take much to toss them around.

For our surface interval and second dive we moved around to Ghost Beach to get some protection from South Island. We pulled up on the beach for our surface interval and ate an early lunch. We found a whole heap of clam and trochus shells around the rocks at one end of the beach. An old Aboriginal shell midden perhaps?

Ghost Beach

Ghost Beach

While we were eating our lunch we watched another research boat with three divers on board, pull up across the channel. We headed back to our boat to gear up for our second dive shortly after they had entered the water. Our second dive went well and we called it a day after 75 minutes. As we were getting back on board our boat I saw what I thought was the same research boat across the way from us with someone on board waving their arms above their head. I thought that 2 divers might have gone missing or worse! So we hauled in the anchor and gunned the engine across to the other boat. Thankfully when we got there it was another researcher who needed help locating some lost equipment (over $10k worth of gear!). The other divers had finished their dive and headed back to the station and this researcher had pulled up in the mean time. Phew! It certainly had the adrenalin pumping.

The equipment had been marked with a GPS, but for whatever reason, the GPS unit was showing the mark several kilometres out to sea. We searched the area and located the equipment and attached a marker buoy to it. Hopefully, the buoy won’t get blown away with the wind. We were offered a free meal for our help, which we gladly accepted. I took stock of our supplies the other night and they’re running pretty low. So a free meal is really appreciated!

The public phone at the station has finally been fixed after the cyclone toppled the communications tower. I’ve been trying to get through to my partner for the last few nights with no luck, so it’ll be fantastic to be able to make a call and have a good talk.

Day 14 15/8/14

We’ve been seeing quite a few of the species that I’ve been calling G. bilineatus out on the reefs here, but I’m not sure that it is G. bilineatus as G. bilineatus has only been documented from the Red Sea as far as I know. I haven’t been able to get a clear photograph of one in the field to send out to an expert. I was talking about this dilemma at breakfast this morning and Gabby had the bright idea of collecting a few to photograph under the dissection microscope. So I spent the morning checking that our collection permit and animal ethics approvals would cover us for collecting and keeping a few fish over night. All good there! So we packed some coral and fish tagging gear into our field bag and geared up for a dive.

As I was gearing up I remembered that I had downloaded the GPS track from the day we previously found this species, so I ran back to our lab to look at the location where we’d seen them. No one was in the lab when I got there and as I was sitting at my computer I heard a crackling noise from behind me. I turned around and saw that a ceramic mortar and pestle with a bunch of lab instruments had spontaneously combusted! our lab-mate had been sterilising his equipment with ethanol and flaming it, pretty standard practice, but some of the ethanol hadn’t evaporated and had pooled in the bottom. The heat from the instruments was evidently just enough to ignite it! Exciting stuff!

We had previously found some of the G. bilineatus out near Horseshoe reef so we headed back there for our dive. It wasn’t as windy today as it has been, but there was a pretty uncomfortable swell on the surface and it was raining. We found the corals where we’d previously seen the fish pretty easily and set about collecting the fish. As I was trying to get one of the unconscious gobies out of an A. gemmifera, a coral crab grabbed hold of it and started picking at the poor goby’s fins! I had to poke the crab with a cable tie to get it to bugger off. I finally got the fish out of the coral and the poor thing had scarring down its sides. It is alive and well now though 🙂 We ended up with three brown ones and two light ones. All have the blue lines through the eye, but the light ones have a red pattern along the base of the dorsal fins which dissipates into spots at the head (see pictures below).

Back at the station we got out the tattooing gear and gave each fish an individual marking since they were all being stored in the same tank. This will allow us to identify which fish came from which coral when we release them tomorrow. I have accidentally released a fish into the wrong coral before and it knew straight away. It didn’t want to come out of the bag and swam away from the coral as soon as it was free. So we want to avoid that in the future.

In the afternoon I put the fish into smaller plastic bags to take photographs of them. The brown ones actually lost their colour when they went into the plastic bag, probably a stress reaction. In this state they look very similar to the light ones including the red pattern along the base of the dorsal spine. Once back in the tank, they regain their brown colouration. Interestingly, the light ones don’t change colour at all.

dark variant

dark variant

Light variant

Light variant

Dark variant - colour loss

Dark variant – colour loss

Day 15 16/8/14

It’s BBQ night tonight and Grant and I don’t have any BBQ food left! We managed to borrow a fishing line and some lures from Dom, so we’re hoping to catch a fish for tonight.

Today is the first day where there’s been no wind! It was beautiful on the water. We did a quick snorkel in the morning to take back the fish we’d collected yesterday then took advantage of the good weather and went outside the lagoon to a site called the Washing Machine. Underwater, the site had been hit pretty hard by the cyclone, but there were lots of small corals that survived. We only found three G. rivulatus and a G. spp D. the whole time we were diving. I collected the G. spp D for measurement and fin clipping because I didn’t find too many of them last time. We ran one transect on a colony of G. rivulatus but there was not much around it. It’s still useful data though as it will be indicative of a low habitat saturation site.

G. spp D

G. spp D

During our surface interval we threw the fishing line in and trolled down the east wall, in the yellow marine park zone. We got a couple of hits, but nothing hooked up. Our BBQ night was looking a little sketchy.

After we’d tried fishing for about an hour we were going to head to our second site, but as I throttled up, the engine was only revving at about half its usual RPM. The boat wouldn’t even get on the plane. So we limped back to the station. When we got there and told Lance (one of the station caretakers) about our engine troubles, he tried to take it for a test run to diagnose the problem, but when he twisted the throttle he got no response at all on the engine. We were lucky to have made it back to the station at all! Lance dragged the boat out of the water with the tractor and set about the repairs while I gave the hull a clean.

Since our boat was high and dry for the afternoon, we decided to join a group going out for a fun dive at Coconut Beach. Grant decided to freedive instead of taking all the SCUBA gear again. I love diving so I got all my gear together. The dive was really lovely, with beautiful clear water and reef sharks and turtles and octopus and cuttlefish and of course, all of the usual reef fish.

Grant dropping down to say hello to the divers

Grant dropping down to say hello to the divers

After the dive, Grant joined Lance and Maryanne on a quick fishing trip back up to the north side of Lizard Island. They got back just after sunset, with grant carrying a great big grin and an even bigger shark mackerel! Our BBQ night was saved! Apparently it was good afternoon for fishing. Another group came back with a huge Spanish mackerel and four smaller shark mackerel.

We coated our fillets in flour with a bit of salt, pepper and lime zest and cooked them on the BBQ hot plate. They were fantastic. Thanks Grant!

Day 16 17/8/14

The wind has been increasing steadily again today, but it was still low enough to get outside the lagoon. Lance has done great job on our engine. It runs so much more smoothly than when we started using it.

We went out to Washing Machine again for our first dive and ran a couple of transects. The water was beautifully clear today, but it was low tide, so the dive was a bit surgey. Grant found a beautiful big lion fish at the base of the shelf we were diving.

Lion fish at the Washing Machine

Lion fish at the Washing Machine

Working hard

Working hard

After our dive we did a bit more fishing, taking advantage of the good conditions. Grant pulled in a nice sized shark mackerel again. We are definitely set for food now.

We did our second dive at Lizard Head. The coral there was in really good condition. It didn’t even look like a cyclone had come through though. I found a couple of my corals and a few gobies, but the corals were so thick I couldn’t get them out. I need to decide now whether to devote the time to get them out so that I can re-measure them or to focus on the habitat saturation surveys. It’s a difficult decision because I haven’t found many of my gobies from last time so the data I’m getting from that component is unlikely to yield anything. But if I don’t get that data it’ll take me six months to re-run it.

Back at the station we filleted and skinned the fish. In the evening we crumbed the fillets and shallow fried them. We served it up with chilli mayonnaise and some salad. It was the best meal we’ve had here at Lizard!

Grant filleting his mackerel

Grant filleting his mackerel